His countenance - In our language the word “countenance” refers to the “face only;” in the original it refers to his “whole person.” His “general aspect, or the appearance of the angel himself,” was, etc.
Like lightning - Peculiarly bright and shining.
His raiment white as snow - Celestial beings are usually represented as clothed in white, Acts 1:10; Daniel 7:9; Revelation 3:4-5; Revelation 4:4; Revelation 7:13-14. White, among the Jews, was the symbol of “purity or innocence.”